JP5019737B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device and a driving method thereof.

  2. Description of the Related Art In recent years, attention has been focused on an individual recognition technique in which an ID (individual identification number) is given to an individual object to clarify information such as a history of the object and to be useful for production and management. Among them, development of semiconductor devices that transmit and receive data without contact using electromagnetic fields or radio waves is underway. As such a semiconductor device, a wireless chip (also referred to as an ID tag, an IC tag, an IC chip, an RF tag (Radio Frequency), a wireless tag, an electronic tag, or an RFID tag (Radio Frequency Identification)) or the like is used in the company, in the market, Etc. have begun to be introduced.

  Many of semiconductor devices currently in practical use have a circuit (also referred to as an IC (Integrated Circuit) chip) using a semiconductor substrate and an antenna, and the IC chip is composed of a memory, a control circuit, and the like.

  Further, according to the configuration of the memory provided in the IC chip, the means for writing and reading information is classified into various methods. For example, when a mask ROM is used for the memory circuit, data cannot be written except when the chip is manufactured. In this case, since data cannot be written except when the chip is manufactured and it is not easy to use, an ID chip capable of writing data other than during chip manufacturing is required.

  On the other hand, when an EEPROM or the like is used for the memory circuit, the user can freely rewrite the contents, but a person other than the user can rewrite the information and can forge. (For example, Non-Patent Document 1) Therefore, security measures are not sufficiently taken at present, and a measure capable of preventing forgery due to rewriting or the like is required.

Further, an element capable of storing more data with less power is demanded as a memory, and research and development are actively performed.
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  An object of the present invention is to provide a semiconductor device in which data can be written other than at the time of chip manufacturing and forgery by rewriting can be prevented. Furthermore, an object of the present invention is to provide an inexpensive semiconductor device having a memory element that can be easily formed and a driving method thereof.

  In order to solve the above problems, the present invention takes the following measures.

  The semiconductor device of the present invention is provided at an intersection of a plurality of bit lines extending in a first direction, a plurality of word lines extending in a second direction different from the first direction, and the bit lines and the word lines. A memory cell array having a plurality of memory cells, and a memory element provided in the memory cell. The memory element includes a conductive layer that forms a bit line, an organic compound layer, and a conductive layer that forms a word line. It is characterized by a laminated structure.

  According to another configuration of the semiconductor device of the present invention, a plurality of bit lines extending in a first direction, a plurality of word lines extending in a second direction different from the first direction, a bit line and a word line are provided. A memory cell array having a plurality of memory cells provided at the intersection of the memory cell, a memory element provided in the memory cell, and a conductive layer functioning as an antenna, the memory element comprising a conductive layer constituting a bit line, It is characterized by a laminated structure of an organic compound layer and a conductive layer constituting a word line.

  According to another structure of the semiconductor device of the present invention, in the above structure, the conductive layer functioning as an antenna is provided in the same layer as the conductive layer forming the bit line or the conductive layer forming the word line. It is characterized by.

  Another structure of the semiconductor device of the present invention is characterized in that, in the above structure, one or both of the conductive layer forming the bit line and the conductive layer forming the word line have translucency.

  According to another configuration of the semiconductor device of the present invention, a plurality of bit lines extending in a first direction, a plurality of word lines extending in a second direction different from the first direction, a bit line and a word line are provided. A memory cell array having a plurality of memory cells surrounded by the memory cell, the memory cell having a transistor and a memory element electrically connected to the transistor, the memory element having a source region or a drain region of the transistor It is characterized by a laminated structure of a first conductive layer, an organic compound layer, and a second conductive layer which are electrically connected.

  According to another configuration of the semiconductor device of the present invention, a plurality of bit lines extending in a first direction, a plurality of word lines extending in a second direction different from the first direction, a bit line and a word line are provided. A memory cell array having a plurality of memory cells surrounded by a conductive layer functioning as an antenna. The memory cell includes a transistor and a memory element electrically connected to the transistor. A stacked structure of a first conductive layer, an organic compound layer, and a second conductive layer which are electrically connected to a source region or a drain region of a transistor is characterized.

  Another structure of the semiconductor device of the present invention is characterized in that, in the above structure, the conductive layer functioning as an antenna is provided in the same layer as the first conductive layer or the second conductive layer. .

  Another structure of the semiconductor device of the present invention is characterized in that, in the above structure, one or both of the first conductive layer and the second conductive layer have a light-transmitting property.

  Another structure of the semiconductor device of the present invention is characterized in that in the above structure, the distance between the first conductive layer and the second conductive layer is changed by writing to the memory element.

  Another structure of the semiconductor device of the present invention is characterized in that, in the above structure, the organic compound layer is an electron transport material or a hole transport material.

Another structure of the semiconductor device of the present invention is characterized in that, in the above structure, the conductivity of the organic compound layer is 10 ⁻¹⁵ S / cm or more and 10 ⁻³ S / cm or less.

  Another structure of the semiconductor device of the present invention is characterized in that, in the above structure, the thickness of the organic compound layer is 5 to 60 nm.

  According to another aspect of the present invention, there is provided a method for driving a semiconductor device comprising: a plurality of bit lines extending in a first direction; a plurality of word lines extending in a second direction different from the first direction; A memory cell array having a plurality of memory cells provided at the intersection and a memory element provided in the memory cell, the memory element having an organic compound layer provided between the bit line and the word line By applying a voltage between the bit line and the word line, the electrical resistance of the memory element is changed to write data, and by applying a voltage between the bit line and the word line, the electrical power of the memory element Data is read by reading a resistor.

  According to another driving method of the semiconductor device of the present invention, a plurality of bit lines extending in a first direction, a plurality of word lines extending in a second direction different from the first direction, and the bit lines and word lines A memory cell array including a plurality of memory cells surrounded by a memory cell, the memory cell including a transistor and a memory element electrically connected to the transistor, wherein the memory element is interposed between the pair of conductive layers. It has an organic compound layer provided, and by applying a voltage between a pair of conductive layers, data is written by changing the electrical resistance of the memory element, and a voltage is applied between the bit line and the word line Thus, data is read by reading the electrical resistance of the memory element.

  By using the present invention, it is possible to obtain a semiconductor device in which data can be written (added) other than during chip manufacturing and forgery by rewriting can be prevented. Further, by providing a memory using an organic compound that can be easily formed as a material or a semiconductor device including the memory, an inexpensive semiconductor device and a driving method thereof can be provided.

  In addition, a semiconductor device including a memory element that can be written with low power when data is written to a memory can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below. Note that in the structures of the present invention described below, the same reference numerals are used in common in different drawings.

(Embodiment 1)
The semiconductor device 20 described in this embodiment has a function of communicating data without contact, and includes a power supply circuit 11, a clock generation circuit 12, a data demodulation / modulation circuit 13, a control circuit 14 for controlling other circuits, and an interface. A circuit 15, a memory 16, a data bus 17, and an antenna 18 (antenna coil) are included (FIG. 1A). The power supply circuit 11 is a circuit that generates various power supplies to be supplied to each circuit inside the semiconductor device 20 based on the AC signal input from the antenna 18. The clock generation circuit 12 is a circuit that generates various clock signals to be supplied to each circuit in the semiconductor device 20 based on the AC signal input from the antenna 18. The data demodulation / modulation circuit 13 has a function of demodulating / modulating data communicated with the reader / writer 19. The control circuit 14 has a function of controlling the memory 16. The antenna 18 has a function of transmitting and receiving an electromagnetic field or a radio wave. The reader / writer 19 controls communication with the semiconductor device 20, control, and processing related to the data. The semiconductor device 20 is not limited to the above-described configuration, and may be a configuration in which other elements such as a power supply voltage limiter circuit and cryptographic processing dedicated hardware are added.

  In FIG. 1A, the memory 16 has a structure in which a layer containing an organic compound (hereinafter also referred to as an organic compound layer) is provided between a pair of conductive layers (hereinafter also referred to as an “organic memory element”). It is characterized by that. The memory 16 may include not only a memory composed of an organic memory element but also other memories. Examples of the other memory include one or more memories selected from DRAM, SRAM, FeRAM, mask ROM, PROM, EPROM, EEPROM, and flash memory.

  A memory including an organic memory element (hereinafter also referred to as an organic memory) uses an organic compound material, and changes the electric resistance of the organic memory element by applying light or electric action to the organic compound layer. It is what is generated.

  Next, the structure of the organic memory will be described (FIG. 1B). The organic memory includes a memory cell array 22 in which memory cells 21 including organic memory elements are provided in a matrix, decoders 23 and 24, a selector 25, and a read / write circuit 26.

  The memory cell 21 includes a first conductive layer connected to the bit line Bx (1 ≦ x ≦ m), a second conductive layer connected to the word line Wy (1 ≦ y ≦ n), and an organic compound layer And have. The organic compound layer is provided between the first conductive layer and the second conductive layer.

  Next, a top structure and a cross-sectional structure when the memory cell array 22 is actually manufactured will be described (FIGS. 2A and 2B). Note that the memory cell array 22 includes a first conductive layer 27 extending in a first direction and a second direction extending in a second direction perpendicular to the first direction on a substrate 30 having an insulating surface. A conductive layer 28 and an organic compound layer 29 are included. The memory cell 21 is provided at the intersection of the first conductive layer 27 and the second conductive layer 28. The first conductive layer 27 and the second conductive layer 28 are provided in stripes so as to cross each other. An insulating layer 33 is provided between the adjacent organic compound layers 29. An insulating layer 34 that functions as a protective layer is provided so as to be in contact with the second conductive layer 28.

  As the substrate 30, a quartz substrate, a silicon substrate, a metal substrate, a stainless steel substrate, or the like is used in addition to a glass substrate or a flexible substrate. The flexible substrate is a substrate that can be bent flexibly, and examples thereof include a plastic substrate made of polycarbonate, polyarylate, polyethersulfone, and the like. The first conductive layer 27 and the second conductive layer 28 are formed using a known conductive material such as aluminum (Al), copper (Cu), or silver (Ag).

  In the case where data is written to the organic memory by light, one or both of the first conductive layer 27 and the second conductive layer 28 have translucency. The light-transmitting conductive layer is formed using a transparent conductive material such as indium tin oxide (ITO), or formed with a thickness that allows light to pass even if it is not a transparent conductive material. To do.

For the organic compound layer 29, an organic compound material having conductivity (preferably having a conductivity of 10 ⁻¹⁵ S / cm or more and 10 ⁻³ S / cm or less) can be used. For example, 4,4′-bis [ N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: α-NPD), 4,4′-bis [N- (3-methylphenyl) -N-phenylamino] biphenyl (abbreviation: TPD), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenyl Amino] triphenylamine (abbreviation: MTDATA), 4,4′-bis (N- (4- (N, N-di-m-tolylamino) phenyl) -N-phenylamino) biphenyl (abbreviation: DNTPD), etc. Aromatic amines (immediately , Benzene ring - having nitrogen bond) compounds and phthalocyanine _{(abbreviation:} H 2 Pc), copper phthalocyanine (abbreviation: CuPc), or vanadyl phthalocyanine (abbreviation: VOPc), and the high hole transportability of the phthalocyanine compound such as substance Can be used.

In addition, as another organic compound material, 4-dicyanomethylene-2-methyl-6- [2- (1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] -4H-pyran (abbreviation) : DCJT), 4-dicyanomethylene-2-t-butyl-6- [2- (1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DCJTB), Periflanthene, 2,5-dicyano-1,4-bis [2- (10-methoxy-1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] benzene, N, N′-dimethylquinacridone ( Abbreviations: DMQd), coumarin 6, coumarin 545T, 9,9′-bianthryl, 9,10-diphenylanthracene (abbreviation: DPA) and 9,10-bis (2-naphthyl) anthracene (abbreviation) DNA), 2,5,8,11-tetra -t- butyl perylene (abbreviation: TBP), and the like. As a base material for forming a layer in which the light emitting material is dispersed, an anthracene such as 9,10-di (2-naphthyl) -2-tert-butylanthracene (abbreviation: t-BuDNA) is used. Derivatives, carbazole derivatives such as 4,4′-bis (N-carbazolyl) biphenyl (abbreviation: CBP), bis [2- (2-hydroxyphenyl) pyridinato] zinc (abbreviation: Znpp ₂ ), bis [2- (2 Metal complexes such as -hydroxyphenyl) benzoxazolate] zinc (abbreviation: ZnBOX) can be used. In addition, tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), 9,10-bis (2-naphthyl) anthracene (abbreviation: DNA), bis (2-methyl-8-quinolinolato) -4-phenylphenolato- Aluminum (abbreviation: BAlq) or the like can be used.

In addition, as other organic compound materials, 4-dicyanomethylene-2-methyl-6- (1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (abbreviation: DCJT), 4-dicyanomethylene-2-tert-butyl-6- (1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran, perifrantene, 2,5-dicyano-1,4-bis (10-methoxy-1,1,7,7-tetramethyljulolidyl-9-enyl) benzene, N, N′-dimethylquinacridone (abbreviation: DMQd), coumarin 6, coumarin 545T, tris (8-quinolinolato) Aluminum (abbreviation: Alq ₃ ), 9,9′-bianthryl, 9,10-diphenylanthracene (abbreviation: DPA) and 9,10-bis (2-naphthyl) anthracene (abbreviation: D) NA), 2,5,8,11-tetra-t-butylperylene (abbreviation: TBP) and the like. As a base material for forming a layer in which the light emitting material is dispersed, an anthracene such as 9,10-di (2-naphthyl) -2-tert-butylanthracene (abbreviation: t-BuDNA) is used. Derivatives, carbazole derivatives such as 4,4′-bis (N-carbazolyl) biphenyl (abbreviation: CBP), bis [2- (2-hydroxyphenyl) pyridinato] zinc (abbreviation: Znpp ₂ ), bis [2- (2 Metal complexes such as -hydroxyphenyl) benzoxazolate] zinc (abbreviation: ZnBOX) can be used. In addition, tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), 9,10-bis (2-naphthyl) anthracene (abbreviation: DNA), bis (2-methyl-8-quinolinolato) -4-phenylphenolato- Aluminum (abbreviation: BAlq) or the like can be used.

In addition, as the material of the organic compound layer, other materials that can change the electric resistance of the organic memory element by applying light or electric action can be used. For example, a conjugated polymer doped with a compound that generates an acid by absorbing light (a photoacid generator) can be used. Here, polyacetylenes, polyphenylene vinylenes, polythiophenes, polyanilines, polyphenylene ethynylenes, and the like can be used as the conjugated polymer. As the photoacid generator, arylsulfonium salts, aryliodonium salts, o-nitrobenzyl tosylate, arylsulfonic acid p-nitrobenzyl esters, sulfonylacetophenones, Fe-allene complex PF ₆ salts, and the like can be used. .

  Further, as a different structure from the above structure, a rectifying element may be provided between the first conductive layer 27 and the organic compound layer 29 or between the second conductive layer 28 and the organic compound layer 29. (See FIG. 2D). The rectifying element is typically a Schottky diode, a diode having a PN junction, a diode having a PIN junction, or a transistor in which a gate electrode and a drain electrode are connected. Of course, other configurations of diodes may be used. Here, a case where a PN junction diode including semiconductor layers 44 and 45 is provided between the first conductive layer and the organic compound layer is shown. One of the semiconductor layers 44 and 45 is an N-type semiconductor, and the other is a P-type semiconductor. In this manner, by providing an element having a rectifying action, the selectivity of the memory cell can be improved and the margin of the read or write operation can be improved.

  In addition, as illustrated in FIG. 15, a memory 282 including an organic compound layer provided between a pair of conductive layers can be provided over the integrated circuit 281. That is, the integrated circuit 281 may be formed over the substrate 280 and the memory 282 may be formed thereover.

  As described above, since the organic memory element described in this embodiment has a simple structure in which an organic compound layer is provided between a pair of conductive layers, a manufacturing process is simple and an inexpensive semiconductor device can be provided. Further, since the organic memory described in this embodiment is a nonvolatile memory, it is not necessary to incorporate a battery for holding data, and a small, thin, and lightweight semiconductor device can be provided. In addition, since the electrical resistance of the organic memory element changes irreversibly by writing, data can be written (added), but data cannot be rewritten. Then, it is possible to provide a semiconductor device that prevents forgery and ensures security.

  Next, an operation when data is written to the organic memory will be described. Data writing is performed by optical action or electrical action. First, the case of writing data by electrical action will be described (see FIG. 1B). Writing is performed by changing the electrical characteristics of the memory cell. The initial state of the memory cell (the state where no electrical action is applied) is data “0”, and the state where the electrical characteristic is changed is “1”. To do.

  When data “1” is written in the memory cell 21, first, the memory cell 21 is selected by the decoders 23 and 24 and the selector 25. Specifically, the decoder 24 applies a predetermined voltage V2 to the word line W3 connected to the memory cell 21. Further, the bit line B 3 connected to the memory cell 21 is connected to the read / write circuit 26 by the decoder 23 and the selector 25. Then, the write voltage V1 is output from the read / write circuit 26 to the bit line B3. Thus, the voltage Vw = V1−V2 is applied between the first conductive layer and the second conductive layer constituting the memory cell 21. By appropriately selecting the potential Vw, the organic compound layer 29 provided between the conductive layers is changed physically or electrically, and data “1” is written. Specifically, at the read operation voltage, the electrical resistance between the first conductive layer and the second conductive layer in the data “1” state is significantly smaller than that in the data “0” state. It is good to change as follows. For example, it may be appropriately selected from the range of (V1, V2) = (0V, 5-15V), or (3-5V, -12--2V). The voltage Vw may be 5 to 15V, or -5 to -15V. In this case, the distance between the pair of conductive layers provided with the organic compound layer interposed therebetween may change.

  Note that data “1” is controlled not to be written in the memory cell connected to the non-selected word line and the non-selected bit line. For example, unselected word lines and unselected bit lines may be set in a floating state. The first conductive layer and the second conductive layer constituting the memory cell must have characteristics such as diode characteristics that can ensure selectivity.

  On the other hand, when data “0” is written in the memory cell 21, it is not necessary to apply an electrical action to the memory cell 21. In the circuit operation, for example, as in the case of writing “1”, the memory cell 21 is selected by the decoders 23 and 24 and the selector 25, but the output potential from the read / write circuit 26 to the bit line B3 is selected. The potential of the word line W3 or the potential of the non-selected word line is set to the same level, and the electrical characteristics of the memory cell 21 are not changed between the first conductive layer and the second conductive layer constituting the memory cell 21. A voltage (for example, −5 to 5 V) may be applied.

  Next, a case where data is written by optical action will be described. When data is written by an optical action, the organic compound layer 29 is irradiated with laser light from the light-transmitting conductive layer side (herein, the second conductive layer 28). Here, the organic compound layer 29 included in a desired portion of the organic memory element is selectively irradiated with laser light to destroy the organic compound layer 29. Since the destroyed organic compound layer is insulated, the electric resistance increases when an organic memory element including the destroyed organic compound layer is compared with another organic memory element. As described above, data is written by utilizing the change in the electrical resistance between the two conductive layers provided with the organic compound layer 29 sandwiched by the laser light irradiation. For example, when an organic memory element including an organic compound layer not irradiated with laser light is set to “0” data, when writing “1” data, the organic compound layer included in a desired portion of the organic memory element The electrical resistance is increased by selectively irradiating with laser light and destroying.

  Further, when a conjugated polymer doped with a compound that generates an acid by absorbing light (photoacid generator) is used as the organic compound layer 29, when the laser beam is irradiated, the organic compound irradiated with the laser beam Only the organic memory element including the layer has increased conductivity. On the other hand, an organic memory element including an organic compound layer not irradiated with laser light has no conductivity. Therefore, by selectively irradiating a desired portion of the organic compound layer with laser light, data can be written using the change in the electrical resistance of the organic memory element including the organic compound layer irradiated with the laser light. Do. For example, when an organic memory element including an organic compound layer not irradiated with laser light is set to “0” data, when writing “1” data, the organic compound layer included in a desired portion of the organic memory element A laser beam is selectively irradiated to increase the conductivity.

When irradiating with laser light, the change in the electrical resistance of the organic memory element is realized by irradiating the laser light with a diameter of about μm, although it depends on the size of the memory cell 21. For example, when a laser beam having a diameter of 1 μm passes at a linear velocity of 10 m / sec, the time during which the organic memory element included in one memory cell 21 is irradiated with laser light is 100 nsec. In order to change the phase within a short time of 100 nsec, the laser power is preferably 10 mW and the power density is 10 kW / mm ² . In the case of selectively irradiating laser light, it is preferable to use a pulsed laser irradiation apparatus.

  Here, an example of a laser irradiation apparatus will be briefly described with reference to FIG. A laser irradiation apparatus 1001 includes a computer 1002 (hereinafter, referred to as a PC 1002) that performs various controls when irradiating laser light, a laser oscillator 1003 that outputs laser light, a power source 1004 of the laser oscillator 1003, and laser light. An optical system 1005 (ND filter) for attenuating light, an acousto-optic modulator (AOM) 1006 for modulating the intensity of laser light, and a lens and an optical path for reducing the cross section of the laser light An optical system 1007 composed of a mirror or the like for changing the position, a moving mechanism 1009 having an X-axis stage and a Y-axis stage, a D / A converter 1010 for digital-to-analog conversion of control data output from the PC 1002, The analog voltage output from the D / A converter 1010 A driver 1011 for controlling the acousto-optic modulator 1006, a driver 1012 for outputting a drive signal for driving the moving mechanism 1009, and an autofocus mechanism 1013 for focusing the laser beam on the irradiated object. (FIG. 12).

As the laser oscillator 1003, a laser oscillator that can oscillate ultraviolet light, visible light, or infrared light can be used. Examples of laser oscillators include excimer laser oscillators such as KrF, ArF, XeCl, and XeF, gas laser oscillators such as He, He—Cd, Ar, He—Ne, and HF, YAG, GdVO ₄ , YVO ₄ , YLF, and YAlO _3. A solid-state laser oscillator using a crystal doped with Cr, Nd, Er, Ho, Ce, Co, Ti, or Tm, and a semiconductor laser oscillator such as GaN, GaAs, GaAlAs, or InGaAsP can be used. In the solid-state laser oscillator, it is preferable to apply the fundamental wave or the second to fifth harmonics.

  Next, an irradiation method using a laser irradiation apparatus will be described. When the substrate 30 provided with the organic compound layer 29 is mounted on the moving mechanism 1009, the PC 1002 detects the position of the organic compound layer 29 to be irradiated with laser light by a CCD camera or the like. Next, the PC 1002 generates movement data for moving the movement mechanism 1009 based on the detected position data.

  Thereafter, the PC 1002 controls the output light amount of the acousto-optic modulator 1006 via the driver 1011, so that the laser light output from the laser oscillator 1003 is attenuated by the optical system 1005 and then the acousto-optic modulator 1006. The light amount is controlled so as to be a predetermined light amount. On the other hand, the laser light output from the acousto-optic modulator 1006 is changed in the optical path and beam spot shape by the optical system 1007, condensed by the lens, and then selectively applied to the organic compound layer on the substrate 30. Irradiate.

  At this time, according to the movement data generated by the PC 1002, the movement mechanism 1009 is controlled to move in the X direction and the Y direction. As a result, laser light is irradiated to a predetermined place, the light energy density of the laser light is converted into thermal energy, and the organic compound layer provided on the substrate 30 can be selectively irradiated with the laser light. Note that, here, an example in which the moving mechanism 1009 is moved and laser light irradiation is performed is shown; however, the laser light may be moved in the X direction and the Y direction by adjusting the optical system 1007.

  As described above, the structure of the present invention in which data is written by laser light irradiation can easily manufacture a large number of semiconductor devices. Therefore, an inexpensive semiconductor device can be provided.

  Next, an operation for reading data from the organic memory will be described (see FIGS. 1B and 9). In reading data, the electrical characteristics between the first conductive layer and the second conductive layer constituting the memory cell are different between the memory cell having data “0” and the memory cell having data “1”. Use it. For example, the effective electrical resistance between the first conductive layer and the second conductive layer constituting the memory cell having data “0” (hereinafter simply referred to as the electrical resistance of the memory cell) is R0 at the read voltage. A method of reading data by using the difference in electric resistance when the electric resistance of the memory cell having data “1” is R1 in the read voltage will be described. Note that R1 << R0. As the configuration of the reading / writing circuit, for example, a circuit 26 using a resistance element 46 and a differential amplifier 47 shown in FIG. 9A can be considered. The resistance element 46 has a resistance value Rr, and R1 <Rr <R0. A transistor 48 may be used instead of the resistance element 46, and a clocked inverter 49 may be used instead of the differential amplifier 47 (FIG. 9B). The clocked inverter 49 receives a signal or an inverted signal that becomes Hi when reading and becomes Lo when not reading. Of course, the circuit configuration is not limited to FIG.

  When reading data from the memory cell 21, first, the memory cell 21 is selected by the decoders 23 and 24 and the selector 25. Specifically, the decoder 24 applies a predetermined voltage Vy to the word line Wy connected to the memory cell 21. Further, the bit line Bx connected to the memory cell 21 is connected to the terminal P of the read / write circuit 26 by the decoder 23 and the selector 25. As a result, the potential Vp of the terminal P becomes a value determined by resistance division of Vy and V0 by the resistance element 46 (resistance value Rr) and the memory cell 21 (resistance value R0 or R1). Therefore, when the memory cell 21 has data “0”, Vp0 = Vy + (V0−Vy) * R0 / (R0 + Rr). When the memory cell 21 has data “1”, Vp1 = Vy + (V0−Vy) * R1 / (R1 + Rr). As a result, in FIG. 9A, Vref is selected to be between Vp0 and Vp1, and in FIG. 9B, the change point of the clocked inverter is selected to be between Vp0 and Vp1. Thus, Lo / Hi (or Hi / Lo) is output as the output potential Vout according to the data “0” / “1”, and reading can be performed.

  For example, the differential amplifier 47 is operated at Vdd = 3V, and Vy = 0V, V0 = 3V, and Vref = 1.5V. Assuming that R0 / Rr = Rr / R1 = 9, when the memory cell data is “0”, Vp0 = 2.7 V and Vout is Hi, and when the memory cell data is “1”, Vp1 = 0.3V and Lo is output as Vout. Thus, the memory cell can be read.

  According to the above method, the state of the electric resistance of the organic memory element is read as a voltage value using the difference in resistance value and resistance division. Of course, the reading method is not limited to this method. For example, in addition to using the difference in electrical resistance, reading may be performed using the difference in current value. In addition, when the electrical characteristics of the memory cell have data “0” and “1” and diode characteristics with different threshold voltages, reading may be performed using the threshold voltage difference.

(Embodiment 2)
As described above, the semiconductor device of the present invention has a memory, and a semiconductor device different from the above embodiment will be described below with reference to the drawings.

  The memory 216 includes a memory cell array 222 in which memory cells 221 are provided in a matrix, decoders 223 and 224, a selector 225, and a read / write circuit 226 (FIG. 10). Note that the structure of the memory 216 shown here is merely an example, and other circuits such as a sense amplifier, an output circuit, and a buffer may be included.

  The memory cell 221 includes a first conductive layer connected to the bit line Bx (1 ≦ x ≦ m), a second conductive layer connected to the word line Wy (1 ≦ y ≦ n), a transistor 240, and a memory Element 241 (hereinafter also referred to as organic memory element 241). The memory element 241 has a structure in which an organic compound layer is sandwiched between a pair of conductive layers. The gate electrode of the transistor 240 is connected to the word line Wy, one of the source electrode and the drain electrode is connected to the bit line Bx, and the other is connected to one of the two terminals of the memory element 241. The remaining one terminal of the memory element 241 is connected to a common electrode (potential Vcom).

  Next, a cross-sectional structure of the memory 216 having the above structure will be described (see FIG. 11).

  Here, the cross-sectional structure of the transistor 240 and the organic memory element 241 included in the memory cell array 222 and the CMOS circuit 248 included in the selector 225 is shown. The transistor 240 and the CMOS circuit 248 are provided over the substrate 230, and the organic memory element 241 is formed so as to be electrically connected to the transistor 240.

  The organic memory element 241 is formed of a stacked body of a first conductive layer 243, an organic compound layer 244, and a second conductive layer 245, and an insulating layer 249 is provided between adjacent organic memory elements 241. Is provided. The insulating layer 249 is formed as a partition for separating the plurality of organic memory elements 241. In addition, the source or drain region of the transistor 240 and the first conductive layer 243 included in the organic memory element 241 are electrically connected.

  The first conductive layer 243 and the second conductive layer 245 are formed using a conductive material such as aluminum (Al), copper (Cu), silver (Ag), or titanium (Ti).

  In the case where data is written by an optical action, one or both of the first conductive layer 243 and the second conductive layer 245 are formed using a light-transmitting material such as indium tin oxide (ITO). Or it forms with the thickness which permeate | transmits light. In the case where data is written by an electrical action, there is no particular limitation on the material used for the first conductive layer 243 and the second conductive layer 245.

  As the organic compound layer 244, as described in Embodiment 1 above, a single layer or a stacked structure of any of the above materials can be used.

  In the case where an organic compound material is used for the organic compound layer 244, data is written by applying an optical action or an electrical action such as laser light. When a conjugated polymer material doped with a photoacid generator is used, data is written by an optical action. Data reading does not depend on the material of the organic compound layer 244 and is performed by an electrical action in any case.

  Next, an operation when data is written to the memory 216 will be described (FIGS. 10 and 11).

  First, an operation when data is written by electrical action will be described. Writing is performed by changing the electrical characteristics of the memory cell. The initial state of the memory cell (the state where no electrical action is applied) is data “0”, and the state where the electrical characteristic is changed is “1”. To do.

  Here, a case where data is written to the memory cell 221 in the n-th row and the m-th column will be described. When writing data “1” in the memory cell 221, first, the memory cell 221 is selected by the decoders 223 and 224 and the selector 225. Specifically, the decoder 224 applies a predetermined voltage V22 to the word line Wn connected to the memory cell 221. In addition, the bit line Bm connected to the memory cell 221 is connected to the read / write circuit 226 by the decoder 223 and the selector 225. Then, the write voltage V21 is output from the read / write circuit 226 to the bit line Bm.

  In this manner, the transistor 240 included in the memory cell 221 is turned on, the common electrode and the bit line Bm are electrically connected to the memory element 241, and a voltage of approximately Vw = Vcom−V21 is applied. By appropriately selecting the potential Vw, the organic compound layer 244 provided between the conductive layers is changed physically or electrically, and data “1” is written. Specifically, at the read operation voltage, the electrical resistance between the first conductive layer and the second conductive layer in the data “1” state is significantly smaller than that in the data “0” state. It may be changed as described above, or it may be simply short-circuited. The potential may be appropriately selected from the range of (V21, V22, Vcom) = (5-15V, 5-15V, 0V), or (-12 to 0V, -12 to 0V, 3 to 5V). The voltage Vw may be 5 to 15V, or -5 to -15V. In this case, the distance between the pair of conductive layers provided with the organic compound layer interposed therebetween may change.

  Note that data “1” is controlled not to be written in the memory cell connected to the non-selected word line and the non-selected bit line. Specifically, a potential (for example, 0 V) for turning off the transistor of the memory cell to be connected is applied to the non-selected word line, and the non-selected bit line is in a floating state or approximately equal to Vcom. A potential may be applied.

  On the other hand, when data “0” is written in the memory cell 221, it is not necessary to apply an electrical action to the memory cell 221. In circuit operation, for example, as in the case of writing “1”, the memory cell 221 is selected by the decoders 223 and 224 and the selector 225, but the output potential from the read / write circuit 226 to the bit line Bm is the same as Vcom. Or the bit line Bm is in a floating state. As a result, a small voltage (for example, −5 to 5 V) is applied to the memory element 241 or no voltage is applied, so that the electrical characteristics do not change and data “0” writing is realized.

  Next, a case where data is written by optical action will be described. In this case, the laser irradiation apparatus 232 irradiates the organic compound layer 244 included in the organic memory element 241 with laser light from the light-transmitting conductive layer side (herein, the second conductive layer 245). To do.

  In the case where an organic compound material is used for the organic compound layer 244, the organic compound layer 244 is oxidized or carbonized and insulated by laser light irradiation. Then, the resistance value of the organic memory element 241 irradiated with the laser light increases, and the resistance value of the organic memory element 241 not irradiated with the laser light does not change. When a conjugated polymer material doped with a photoacid generator is used, conductivity is imparted to the organic compound layer 244 by laser light irradiation. That is, conductivity is given to the organic memory element 241 irradiated with the laser beam, and conductivity is not given to the organic memory element 241 not irradiated with the laser beam.

  Next, an operation when data is read by electrical action will be described. Data is read by utilizing the fact that the electrical characteristics of the memory element 241 are different between the memory cell having the data “0” and the memory cell having the data “1”. For example, the electrical resistance of the memory element constituting the memory cell having data “0” is R0 at the read voltage, and the electrical resistance of the memory element constituting the memory cell having data “1” is R1 at the read voltage. A method of reading using the difference will be described. Note that R1 << R0. As the structure of the reading / writing circuit, for example, a circuit 226 using a resistance element 246 and a differential amplifier 247 shown in FIG. 10B can be considered. The resistance element 246 has a resistance value Rr, and R1 <Rr <R0. A transistor 250 may be used instead of the resistance element 246, and a clocked inverter 251 may be used instead of the differential amplifier 247 (FIG. 10C). Of course, the circuit configuration is not limited to FIG.

  When data is read from the memory cell 221 in the nth row and mth column, first, the memory cell 221 is selected by the decoders 223 and 224 and the selector 225. Specifically, the decoder 224 applies a predetermined voltage V24 to the word line Wn connected to the memory cell 221 to turn on the transistor 240. In addition, the bit line Bm connected to the memory cell 221 is connected to the terminal P of the read / write circuit 226 by the decoder 223 and the selector 225. As a result, the potential Vp of the terminal P becomes a value determined by resistance division of Vcom and V0 by the resistance element 246 (resistance value Rr) and the memory element 241 (resistance value R0 or R1). Therefore, when the memory cell 221 has data “0”, Vp0 = Vcom + (V0−Vcom) * R0 / (R0 + Rr). When the memory cell 221 has data “1”, Vp1 = Vcom + (V0−Vcom) * R1 / (R1 + Rr). As a result, in FIG. 10B, Vref is selected to be between Vp0 and Vp1, and in FIG. 10C, the changing point of the clocked inverter 251 is between Vp0 and Vp1. By selecting the output potential Vout, Lo / Hi (or Hi / Lo) is output according to the data “0” / “1”, and reading can be performed.

  For example, the differential amplifier is operated at Vdd = 3V, and Vcom = 0V, V0 = 3V, and Vref = 1.5V. Assuming that R0 / Rr = Rr / R1 = 9 and the on-resistance of the transistor 240 can be ignored, when the data in the memory cell is “0”, Vp0 = 2.7V and Vout is output as Hi, When the data of “1” is “1”, Vp1 = 0.3 V and Lo is output as Vout. Thus, the memory cell can be read.

  According to the above method, the voltage value is read by utilizing the difference in resistance value of the memory element 241 and the resistance division. Of course, the reading method is not limited to this method. For example, in addition to using the difference in electrical resistance, reading may be performed using the difference in current value. In addition, when the electrical characteristics of the memory cell have data “0” and “1” and diode characteristics with different threshold voltages, reading may be performed using the threshold voltage difference.

  Note that this embodiment mode can be freely combined with the above embodiment modes.

(Embodiment 3)
Data writing to the organic memory included in the semiconductor device 20 of the present invention is performed by light or electrical action. When writing data by light, if a plurality of semiconductor devices 20 are formed on the flexible substrate 31 and then laser light is irradiated by the laser light irradiation means 32, data writing can be made continuously and easily. It can be carried out. Further, if such a manufacturing process is employed, a large number of semiconductor devices 20 can be easily manufactured (FIG. 3A). Therefore, an inexpensive semiconductor device 20 can be provided.

  In addition, the organic compound layer included in the organic memory element can be heated and heated to a temperature equal to or higher than the melting point to be intentionally dissolved or destroyed. That is, data writing can be performed by heat treatment if the heating temperature is properly used. Therefore, a manufacturing process using different heating temperatures may be used. For example, the flexible substrate 31 on which a plurality of semiconductor devices are formed is used as the roll 51 (FIG. 3B). Then, data may be written by using the heating means 52 with different heating temperatures during the heat treatment. The heating means 52 is controlled by the control means 53.

  Note that this embodiment mode can be freely combined with the above embodiment modes.

(Embodiment 4)
As an example of a utilization form of the semiconductor device of the present invention, the organic memory element is provided and data can be read and written in a non-contact manner. Data transmission formats are broadly divided into three types: electromagnetic coupling method that communicates by mutual induction with a pair of coils facing each other, electromagnetic induction method that communicates by induction electromagnetic field, and radio wave method that communicates using radio waves. However, any method may be used. There are two ways of providing the antenna 18 used for data transmission. One is the case where the antenna 18 is provided on a substrate 36 provided with a plurality of elements including an organic memory element (FIGS. 4A and 4C). )) And the other is a case where a terminal portion 37 is provided on a substrate 36 provided with a plurality of elements including an organic memory element and the antenna 18 is provided so as to be connected to the terminal portion 37 (FIG. 4B). ), (D)). Here, a plurality of elements provided on the substrate 36 are referred to as an element group 35.

  In the case of the former configuration (FIGS. 4A and 4C), the element group 35 and a conductive layer functioning as the antenna 18 are provided over the substrate 36. In the illustrated configuration, a conductive layer functioning as the antenna 18 is provided in the same layer as the second conductive layer 28. However, the present invention is not limited to the above configuration, and the antenna 18 may be provided in the same layer as the first conductive layer 27, or an insulating film is provided so as to cover the element group 35, and the antenna 18 is provided on the insulating film. May be provided.

  In the case of the latter configuration (FIGS. 4B and 4D), the element group 35 and the terminal portion 37 are provided on the substrate 36. In the configuration shown in the figure, a conductive layer provided in the same layer as the second conductive layer 28 is used as the terminal portion 37. Then, a substrate 38 provided with the antenna 18 is bonded so as to be connected to the terminal portion 37. Conductive particles 39 and a resin 40 are provided between the substrate 36 and the substrate 38.

  If a plurality of element groups 35 are formed on a substrate having a large area and then completed by being divided, an inexpensive element group 35 can be provided. Examples of the substrate used at this time include a glass substrate and a flexible substrate.

  A plurality of transistors and organic memory elements included in the element group 35 may be provided across a plurality of layers. That is, it may be formed in multiple layers. When forming the element group 35 extending over a plurality of layers, an interlayer insulating film is used. As the material of the interlayer insulating film, a resin material such as an epoxy resin or an acrylic resin, or a resin material such as a permeable polyimide resin is used. A compound material having a siloxane material such as a siloxane resin, a material containing a water-soluble homopolymer and a water-soluble copolymer, or an inorganic material may be used. A siloxane material corresponds to a material including a Si—O—Si bond. Siloxane has a skeleton structure formed of a bond of silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (for example, an alkyl group or an aromatic hydrocarbon) is used. A fluoro group may be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as a substituent.

  As a material of the interlayer insulating film, a low dielectric constant material may be used for the purpose of reducing parasitic capacitance generated between the layers. If the parasitic capacitance is reduced, high-speed operation is realized and low power consumption is realized.

The plurality of transistors included in the element group 35 may use any semiconductor such as an amorphous semiconductor, a microcrystalline semiconductor, a microcrystalline semiconductor, a polycrystalline semiconductor, and an organic semiconductor as an active layer. In order to obtain the active layer, an active layer crystallized using a metal element as a catalyst or an active layer crystallized by a laser irradiation method may be used. In addition, a semiconductor layer formed by a plasma CVD method using SiH ₄ / F ₂ gas or SiH ₄ / H ₂ gas (Ar gas), or a semiconductor layer that has been subjected to laser irradiation may be used as the active layer. .

  The plurality of transistors included in the element group 35 includes a crystalline semiconductor layer (low-temperature polysilicon layer) crystallized at a temperature of 200 to 600 degrees (preferably 350 to 500 degrees), or a temperature of 600 degrees or more. A crystalline semiconductor layer (high-temperature polysilicon layer) crystallized in (1) can be used. When a high-temperature polysilicon layer is formed on a substrate, a quartz substrate may be used because a glass substrate may be vulnerable to heat.

The active layer (especially the channel region) of the transistor included in the element group 35 has a concentration of 1 × 10 ¹⁹ atoms / cm ³ to 1 × 10 ²² atoms / cm ³ , preferably 1 × 10 ¹⁹ atoms / cm ^{3 to} 5. Hydrogen or a halogen element is preferably added at a concentration of × 10 ²⁰ atoms / cm ³ . If it does so, the active layer with few defects and being hard to produce a crack can be obtained.

In addition, a barrier film that blocks contaminants such as alkali metals may be provided so as to enclose the transistors included in the element group 35 or to enclose the element group 35 itself. Then, the element group 35 that is not contaminated and has improved reliability can be provided. As the barrier film, a silicon nitride film, a silicon nitride oxide film, a silicon oxynitride film, or the like can be given.
The thickness of the active layer of the transistor included in the element group 35 is 20 nm to 200 nm, preferably 40 nm to 170 nm, more preferably 45 nm to 55 nm, 145 nm to 155 nm, and still more preferably 50 nm and 150 nm. As a result, it is possible to provide the element group 35 that is unlikely to crack even when bent.

  In addition, the crystal forming the active layer of the transistor included in the element group 35 is preferably formed so as to have a crystal grain boundary extending in parallel with the carrier flow direction (channel length direction). Such an active layer may be formed of a continuous wave laser or a pulsed laser operating at 10 MHz or higher, preferably 60 to 100 MHz.

The S value (subthreshold value) of the transistors included in the element group 35 is 0.35 V / dec or less (preferably 0.09 to 0.25 V / dec) and the mobility is 10 cm ² / Vs or more. Good. Such characteristics can be realized by forming the active layer with a continuous wave laser or a pulsed laser operating at 10 MHz or higher.

  The element group 35 has a characteristic of 1 MHz or more, preferably 10 MHz or more (at 3 to 5 V) at the ring oscillator level. Alternatively, the frequency characteristic per gate is 100 kHz or more, preferably 1 MHz or more (at 3 to 5 V).

  The antenna 18 may be formed using a droplet discharge method with a conductive paste containing nanoparticles such as gold, silver, and copper. The droplet discharge method is a general term for a method of forming a pattern by discharging droplets such as an ink jet method or a dispenser method, and has various advantages such as an improvement in material utilization efficiency.

  With the above structure, an RFID tag with a very small plane area of 1 cm × 1 cm can be manufactured.

  In the semiconductor device described in this embodiment, an integrated circuit formed using an IC chip may be mounted on the element group 35. By mounting an integrated circuit formed using an IC chip, the write voltage of the memory element can be set to 14 V or higher. In addition, since it is possible to reduce the area of the writing circuit and the reading circuit of the memory element, the size (planar area) of the RFID tag on which all these circuits are mounted can be made smaller than 1 cm × 1 cm. It is.

  The substrate 42 provided with the element group 35 may be used as it is. However, in order to add value, the element group 35 on the substrate 42 is peeled off (FIG. 5A), and the element group 35 is removed. You may affix on the flexible substrate 43 (FIG.5 (B)).

The element group 35 is peeled from the substrate 42 by (1) providing a metal oxide film between the substrate 42 and the element group 35 having high heat resistance, and weakening the metal oxide film by crystallization. (2) An amorphous silicon film containing hydrogen is provided between the substrate 42 having high heat resistance and the element group 35, and the amorphous silicon film is removed by laser light irradiation or etching, A method of peeling the element group 35, and (3) the element group 35 is removed by mechanically removing or removing the substrate 42 having high heat resistance by etching with a gas such as a solution or CF _3. A method of cutting off the above may be used.

In addition to the above method, a metal film functioning as a peeling layer between the substrate 42 and the element group 35 (for example, tungsten (W), molybdenum (Mo), titanium (Ti), tantalum (Ta), cobalt (Co )), Metal oxide film (for example, tungsten oxide (WOx), molybdenum oxide (MoOx), titanium oxide (TiOx), tantalum oxide (TaOx), cobalt oxide (CoOx)) or metal film and metal oxide It is also possible to provide a laminated structure with the film (for example, W and WOx, Mo and MoOx, Ti and TiOx, Ta and TaOx, Co and CoOx), and peel off the substrate 42 and the element group 35 using physical means. It is. For example, in FIG. 11, an element group such as the transistor 240, the CMOS circuit 248, and the organic memory element 241 is provided on the substrate 230 via these separation layers, and then the element group is separated from the substrate 230. In addition, before peeling, the part which avoided the transistor 240, the CMOS circuit 248, and the organic memory element 241 is selectively irradiated with a laser beam to expose the peeling layer, thereby facilitating physical peeling. . In addition, after an opening is selectively formed to expose the peeling layer, a part of the peeling layer is removed with an etching agent such as halogen fluoride (eg, ClF ₃ ), and then the element is removed from the substrate 42. Groups can also be physically separated.

  The peeled element group 35 may be attached to the flexible substrate 43 using a commercially available adhesive, for example, an adhesive such as an epoxy resin adhesive or a resin additive.

  As described above, when the element group 35 is bonded to the flexible substrate 43, it is possible to provide a semiconductor device that is thin, light, and difficult to break even when dropped. Moreover, since the flexible substrate 43 has flexibility, it can be bonded on a curved surface or an irregular shape, and various uses can be realized. For example, a wireless tag which is one embodiment of the semiconductor device 20 of the present invention can be attached to a curved surface such as a medicine bottle (FIGS. 5C and 5D). Furthermore, if the substrate 42 is reused, an inexpensive semiconductor device can be provided.

  Note that this embodiment mode can be freely combined with the above embodiment modes.

(Embodiment 5)
In this embodiment, a case where a flexible semiconductor device is formed by using a separation process will be described (FIG. 6A). The semiconductor device includes a flexible protective layer 2301, a flexible protective layer 2303 including an antenna 2304, and an element group 2302 formed by a peeling process. An antenna 2304 formed over the protective layer 2303 is electrically connected to the element group 2302. In the illustrated configuration, the antenna 2304 is formed only over the protective layer 2303; however, the present invention is not limited to this configuration, and the antenna 2304 may be formed over the protective layer 2301. Note that a barrier film made of a silicon nitride film or the like is preferably formed between the element group 2302 and the protective layers 2301 and 2303. Then, a semiconductor device with improved reliability can be provided without the element group 2302 being contaminated.

  The antenna 2304 is preferably made of silver, copper, or a metal plated with them. The element group 2302 and the antenna 2304 are connected to each other by performing UV treatment or ultrasonic treatment using an anisotropic conductive film. However, the present invention is not limited to this method, and various methods can be used.

The thickness of the element group 2302 sandwiched between the protective layers 2301 and 2303 is preferably 5 μm or less, preferably 0.1 μm to 3 μm (FIG. 6B). Further, when the thickness when the protective layers 2301 and 2303 are overlapped is defined as d, the thickness of the protective layers 2301 and 2303 is preferably (d / 2) ± 30 μm, more preferably (d / 2) ± 10 μm. And In addition, the thickness of the protective layers 2301 and 2303 is preferably 10 μm to 200 μm. Furthermore, the area of the element group 2302 is 5 mm square (25 mm ² ) or less, and desirably has an area of 0.3 mm square to 4 mm square (0.09 mm ^{2 to} 16 mm ² ).

  Since the protective layers 2301 and 2303 are formed of an organic resin material, they have a strong characteristic against bending. In addition, the element group 2302 itself formed by the separation process also has a stronger characteristic against bending than a single crystal semiconductor. Since the element group 2302 and the protective layers 2301 and 2303 can be in close contact with each other so that there is no gap, the completed semiconductor device itself has a strong characteristic against bending. The element group 2302 surrounded by the protective layers 2301 and 2303 may be arranged on the surface or inside of another solid object, or may be embedded in paper.

  The case where an element group formed by a peeling process is attached to a substrate having a curved surface will be described (FIG. 6C). In the drawing, one transistor selected from an element group formed by a peeling process is illustrated. This transistor is linear in the direction of current flow. That is, the positions of the drain electrode 2305 to the gate electrode 2307 to the source electrode 2306 are linear. The direction in which the current flows and the direction in which the substrate draws an arc are arranged perpendicularly. With such an arrangement, even when the substrate is bent and an arc is drawn, the influence of stress is small, and fluctuations in characteristics of transistors included in the element group can be suppressed.

  Further, in order to prevent destruction of active elements such as transistors due to stress, the area of the active region (silicon island portion) of the active elements is 1% to 50% (preferably with respect to the entire area of the substrate). 1 to 30%). In a region where there is no active element such as a TFT, a base insulating film material, an interlayer insulating film material, and a wiring material are mainly provided. The area other than the active region such as a transistor is preferably 60% or more of the entire area of the substrate. In this way, it is possible to provide a semiconductor device that is easy to bend but has a high degree of integration. This embodiment can be freely combined with the above embodiment modes and embodiments.

  Note that this embodiment mode can be freely combined with the above embodiment modes.

(Embodiment 6)
When an organic memory is integrated in the semiconductor device of the present invention, it is preferable to have the following characteristics.

  The reading time is preferably 1 nsec to 100 μsec in order to operate at a logic circuit operating frequency (typically 10 kHz to 1 MHz) in a semiconductor device capable of exchanging data without contact, such as a wireless chip. In the present invention, since the read operation does not need to change the characteristics of the organic compound, a read time of 100 μsec or less can be realized.

  Of course, the writing time should be short, but the writing operation is rarely performed, and depending on the application, 100 nsec to 10 msec / bit is permissible. For example, when writing 256 bits, it takes 2.56 seconds if 10 msec / 1 bit. In the present invention, the write operation needs to change the characteristics of the organic compound, and takes more time than the read operation, but a write time of 10 msec or less can be realized. It is possible to reduce the writing time by increasing the writing voltage or parallelizing the writing.

  The storage capacity of the memory is preferably about 64 bits to 64 Mbits. As a usage form of a semiconductor device such as a wireless chip, when the semiconductor device stores only a UID (Unique Identifier) and other slight information, and the main data uses another file server, about 64 bits to 8 kbits. If you have. When data such as history information is stored in the semiconductor device, the storage capacity of the memory is preferably large, and preferably about 8 kbit to 64 Mbit.

  In addition, the communication distance of a semiconductor device such as a wireless chip is closely related to the power consumption of the semiconductor device, and in general, the smaller the power consumption, the larger the communication distance can be realized. In particular, it is preferable that the read operation is 1 mW or less. In the writing operation, the communication distance may be short depending on the application, and even power consumption larger than that in the reading operation is allowed. For example, it is preferably 5 mW or less. In the present invention, the power consumption of the organic memory at the time of reading depends of course on the storage capacity and the operating frequency, but 10 μW to 1 mW can be realized. Since the write operation requires a higher voltage than the read operation, the power consumption increases. Although this also depends on the storage capacity and the operating frequency, 50 μW to 5 mW can be realized.

  The area of the memory cell is preferably small, and a 100 nm square to 30 μm square can be realized. In a passive type in which a memory cell does not have a transistor, the memory cell area is determined by the wiring width, and a small memory cell size of about the minimum processing dimension can be realized. In the active type having one transistor in the memory cell, although the area for arranging the transistor is increased, a smaller memory cell area can be realized as compared with a DRAM having a capacitor and an SRAM using a plurality of transistors. By realizing a memory cell area of 30 μm square or less, the memory cell array area can be reduced to 1 mm square or less for a 1 kbit memory. Further, by realizing a memory cell area of about 100 nm square, the memory cell array area can be reduced to 1 mm square or less for a 64 Mbit memory. As a result, the chip area can be reduced.

  Note that the characteristics of these organic memories depend on the characteristics of the memory element. As a characteristic of the memory element, it is preferable that the voltage necessary for electrical writing can be written at a low voltage within a range where writing is not performed in reading, and is preferably 5 to 15 V, more preferably 5 to 10 V. In addition, the value of the current flowing through the memory element during writing is preferably about 1 nA to 30 μA. With such values, power consumption can be kept low, and the booster circuit can be downsized to reduce the chip area. The time required to change the characteristics by applying a voltage to the memory element is preferably 100 nsec to 10 msec corresponding to the writing time of the organic memory. The area of the memory element is preferably 100 nm square to 10 μm square. With such values, a small memory cell can be realized and the chip area can be reduced.

  Note that this embodiment can be freely combined with the above embodiment.

(Embodiment 7)
Although the semiconductor device of the present invention has a wide range of uses, for example, a wireless tag which is one form of the semiconductor device 20 of the present invention is a banknote, a coin, securities, certificates, bearer bonds, packaging containers, books And recording media, personal items, vehicles, foods, clothing, health supplies, daily necessities, medicines, electronic devices, and the like.

  Banknotes and coins are money that circulates in the market, and include those that are used in the same way as money in a specific area (cash vouchers), commemorative coins, and the like. Securities refer to checks, securities, promissory notes, etc. (FIG. 7A). The certificate refers to a driver's license, resident's card, etc. (FIG. 7B). Bearer bonds refer to stamps, gift certificates, various gift certificates, etc. (FIG. 7C). Packaging containers refer to wrapping paper for lunch boxes, plastic bottles, and the like (FIG. 7D). Books refer to books, books, and the like (FIG. 7E). The recording media refer to DVD software, video tapes, and the like (FIG. 7F). Personal belongings refer to bags, glasses, and the like (FIG. 7G). The vehicles refer to vehicles such as bicycles, ships, and the like (see FIG. 7H). Foods refer to food products, beverages, and the like. Clothing refers to clothing, footwear, and the like. Health supplies refer to medical equipment, health equipment, and the like. Livingware refers to furniture, lighting equipment, and the like. Chemicals refer to pharmaceuticals, agricultural chemicals, and the like. Electronic devices refer to liquid crystal display devices, EL display devices, television devices (TV receivers, flat-screen TV receivers), mobile phones, and the like.

  Forgery can be prevented by providing wireless tags on bills, coins, securities, certificate documents, bearer bonds, and the like. In addition, it is possible to improve the efficiency of inspection systems and rental store systems by providing wireless tags for personal items such as packaging containers, books, recording media, personal items, foods, daily necessities, and electronic devices. it can. By providing wireless tags for vehicles, health supplies, medicines, etc., counterfeiting and theft can be prevented, and medicines can prevent mistakes in taking medicines. As a method of providing the wireless tag, the wireless tag is provided on the surface of the article or embedded in the article. For example, a book may be embedded in paper, and a package made of an organic resin may be embedded in the organic resin.

  In this way, the system can be improved in functionality by applying it to a system for managing and distributing goods. For example, there is a case where a reader / writer 95 is provided on the side surface of the portable terminal including the display portion 94 and a wireless tag 96 which is one embodiment of the semiconductor device of the present invention is provided on the side surface of the product 97 (FIG. 8A). ). In this case, when the wireless tag 96 is held over the reader / writer 95, the display unit 94 displays information such as the raw material, the place of origin, and the history of the distribution process. Another example is the case where a reader / writer 95 is provided on the side of the belt conveyor (FIG. 8B). In this case, the product 97 can be easily inspected. This embodiment can be freely combined with the above embodiment modes and embodiments.

  Note that this embodiment mode can be freely combined with the above embodiment modes.

  In this embodiment, an organic memory element is formed over a substrate, and a result of writing data to the organic memory element by an electric action will be described.

  An organic memory element is an element in which a first conductive layer, a first organic compound layer, a second organic compound layer, and a second conductive layer are stacked in this order on a substrate, and the first conductive layer is silicon oxide. And indium tin oxide compound, the first organic compound layer is 4,4′-bis [N- (3-methylphenyl) -N-phenylamino] biphenyl (sometimes abbreviated as TPD), the second The organic compound layer is formed of 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (sometimes abbreviated as α-NPD), and the second conductive layer is formed of aluminum. did. The first organic compound layer was formed with a thickness of 10 nm, and the second organic compound layer was formed with a thickness of 50 nm. The element size was 2 mm × 2 mm.

  First, measurement results of current-voltage characteristics of the organic memory element before data writing by an electrical action and after data writing by an electrical action will be described with reference to FIG.

  In FIG. 13, the horizontal axis represents the voltage value, the vertical axis represents the current value, the plot 261 represents the current-voltage characteristics of the organic memory element when data is written by electrical action, and the plot 262 is after data is written by electrical action. The current-voltage characteristic of the organic memory element is shown. The electrical action was performed by gradually increasing the voltage from 0V. As shown in the plot 261, it can be seen that the current value gradually increases as the voltage is increased, but the current value rapidly increases at about 20V. In other words, this element indicates that writing is possible at 20V. Therefore, the curve of 20V or less in the plot 261 is the current-voltage characteristic of the memory cell that is not written, while the plot 262 shows the current-voltage characteristic of the memory cell that is written.

Further, from FIG. 13, there is a large change in the current-voltage characteristics of the organic memory element before and after data writing. For example, at an applied voltage of 1 V, the current value before data writing is 4.8 × 10 ⁻⁵ mA, whereas the current value after data writing is 1.1 × 10 ² mA. After the data writing, the current value has changed by 7 digits.

  As described above, the resistance value of the organic memory element changes before and after the data is written, and if the change in the resistance value of the organic memory element is read by the voltage value or the current value, the memory value is stored. It can function as a circuit.

  When the organic memory element as described above is used as a memory circuit, a predetermined voltage value (a voltage value that does not cause a short circuit) is applied to the organic memory element every time data is read, and the resistance value is read. Is done. Therefore, the current-voltage characteristic of the organic memory element needs to have a characteristic that does not change even if the read operation is repeated, that is, a predetermined voltage value is repeatedly applied.

  Therefore, the measurement result of the current-voltage characteristics of the organic memory element after the data read operation is described with reference to FIG.

  In this experiment, the current-voltage characteristics of the organic memory element were measured every time the data reading operation was performed once. Since the data reading operation was performed five times in total, the current-voltage characteristics of the organic memory element were measured five times in total. In addition, the current-voltage characteristics are measured for two organic memory elements, that is, an organic memory element whose resistance value has been changed by writing data by an electrical action and an organic memory element whose resistance value has not changed. I went.

  In FIG. 14, the horizontal axis represents the voltage value, the vertical axis represents the current value, the plot 271 represents the current-voltage characteristics of the organic memory element in which the resistance value has been changed by writing data by electrical action, and the plot 272 represents before writing The current-voltage characteristic of the organic memory element is shown.

  As can be seen from the plot 271, the current-voltage characteristic of the organic memory element before writing shows particularly good reproducibility when the voltage value is 1 V or more. Similarly, as can be seen from the plot 272, the current-voltage characteristics of the organic memory element whose resistance value has changed after writing shows particularly good reproducibility when the voltage value is 1 V or more.

  From the above results, it can be seen that the current-voltage characteristics do not change even when the data read operation is repeated a plurality of times. Therefore, the above organic memory element can be used as a memory circuit.

  In this example, the semiconductor device described in the above embodiment is described with reference to FIGS. FIG. 16A is a photograph of the semiconductor device 6001 observed with an optical microscope (reflection type), and FIG. 16B is a schematic diagram of FIG.

  As shown in FIG. 16B, in a semiconductor device 6001, a memory cell array 6002 in which memory cells are provided in a matrix, a part 6003 of a column decoder, a part 6004 of a row decoder, selectors 6007 and 6008, read / write The writing circuit 6005 is observed. A broken line 6009 shown in FIG. 16B shows the second conductive layer of the organic memory element.

  FIG. 17 shows the writing characteristics of the semiconductor device shown in FIG. 16 when the size of the memory cell in the horizontal plane is 5 μm × 5 μm and the writing time is 100 ms. Here, writing was performed by applying a voltage to the organic memory element to short-circuit the organic memory element. In the structure of the organic memory element, the first conductive layer was formed using titanium, the organic compound layer was formed using α-NPD, and the second conductive layer was formed using aluminum. Data was written by applying a pulse voltage to the organic memory element for 100 ms. Note that the memory element here includes a thin film transistor and a memory element.

  In FIG. 17, the horizontal axis indicates the pulse voltage, and the vertical axis indicates the probability of successful writing (writing success rate) below that voltage. Writing started when the writing voltage was set to 5 V, and writing was possible in 6 (9.38%) of the 64 memory cells. Here, 64 memory cells are used, but the number is not limited to 64. For example, only one memory cell can function as a memory. Further, when the writing voltage is 6V, writing can be performed with 33 (52%) memory cells for 64 memories of the semiconductor device, and when the writing voltage is 9V, 45 writings for 64 memory cells of the semiconductor device. When writing is performed with one (70%) memory cells and the writing voltage is 11V, 60 (93%) memory cells can be written with respect to 64 memory cells of the semiconductor device, and the writing voltage is 14V or more. At that time, 100% memory cells of the semiconductor device were successfully written.

  Note that writing was possible even at a writing time of 10 to 100 ms. Further, depending on the structure of the memory cell, writing can be performed in a short time of 10 ms or less.

  From the above results, the memory cell shown in this embodiment can be written with a write voltage of 5 to 14V.

  In this example, current-voltage characteristics when an organic memory element is manufactured over a substrate and data is electrically written to the organic memory element will be described with reference to FIG. Here, writing was performed by applying a voltage to the organic memory element to short-circuit the organic memory element. In FIGS. 18A and 18B, the horizontal axis indicates the voltage applied to the organic memory element, and the vertical axis indicates the current value flowing through the organic memory element.

  Here, a first conductive layer is formed on a glass substrate by a sputtering method, an organic compound layer is formed on the first conductive layer by an evaporation method, and a second conductive layer is formed on the organic compound layer by an evaporation method. To form an organic memory element. The size of the organic memory element formed here in the horizontal plane was 20 μm × 20 μm.

  FIG. 18A shows a current of an organic memory element in which a first conductive layer is formed using titanium, an organic compound layer is formed using α-NPD, and a second conductive layer is formed using aluminum. The voltage characteristics are shown. Note that the thickness of the first conductive layer was 100 nm, the thickness of the organic compound layer was 10 nm, and the thickness of the second conductive layer was 200 nm.

  In FIG. 18B, the first conductive layer is formed using ITO containing silicon oxide, the organic compound layer is formed using the film α-NPD, and the second conductive layer is formed using aluminum. 1 shows current-voltage characteristics of the organic memory device. Note that the thickness of the first conductive layer was 110 nm, the thickness of the organic compound layer was 10 nm, and the thickness of the second conductive layer was 200 nm.

  In FIG. 18A, a plot 6011 shows the current-voltage characteristics of the organic memory element before data is written, a plot 6012 shows the current-voltage characteristics of the organic memory element immediately after the data is written, and a plot 6013 is electrically The current-voltage characteristic when a voltage is applied to the organic memory element in which data is written is shown. The writing voltage at this time was 8.29 V, and the writing current at that time was 0.16 mA.

  In FIG. 18B, a plot 6015 shows the current-voltage characteristics of the organic memory element before data is electrically written, a plot 6016 shows the current-voltage characteristics of the organic memory element immediately after the data is written, and a plot 6017 shows The current-voltage characteristic when a voltage is applied to the organic memory element in which data is electrically written is shown. The write voltage at this time was 4.6 V, and the write current at that time was 0.24 mA. As described above, the organic memory element disclosed in the present invention can be written at a low voltage and has a small current value at the time of writing. Therefore, it is possible to suppress power consumption for writing to the organic memory element.

  18A and 18B are compared, an organic memory element in which the first conductive layer is formed of a titanium layer as shown in FIG. 18A has a certain voltage, in this case 8.29V. Until almost no current flows. However, when the voltage is higher than 8.29 V, the current value of the organic memory element changes abruptly and data is written, so that it is easy to write and read.

  On the other hand, in the organic memory element having the first conductive layer formed of ITO containing silicon oxide, a current gradually flows from around 4.5V. That is, a current flows even before writing. Further, the IV curve after writing is not linear, and the resistance value is larger than that after writing of the organic memory element in which the first conductive layer is formed of titanium. That is, it can be said that the organic memory element having the first conductive layer formed of ITO containing silicon oxide has a small difference in resistance value before and after writing and poor memory characteristics.

  From the above, in order to provide an element having excellent memory characteristics, the first conductive layer is preferably a metal layer, typically a titanium layer.

  In this embodiment, the result of cross-sectional observation after writing of an organic memory element using TEM (Transmission-Electron-Microscope) will be described with reference to the drawings. Here, writing was performed by applying a voltage to the organic memory element to short-circuit the organic memory element.

  First, a first conductive layer having a thickness of 110 nm is formed on a glass substrate by a sputtering method, an organic compound layer having a thickness of 35 nm is formed on the first conductive layer by a vapor deposition method, and vapor deposition is performed on the organic compound layer. A second conductive layer having a thickness of 270 nm was formed by the method to form an organic memory element. Here, the first conductive layer is formed using ITO containing silicon oxide, the organic compound layer is formed using TPD, and the second conductive layer is formed using aluminum. The size of the organic memory element in the horizontal plane was 2 mm × 2 mm.

  Next, a cross section of the organic memory element in which data was written by applying a write voltage to the organic memory element was observed with a TEM. Note that the TEM sample was fabricated by FIB (Focus-Ion-Beam) and finished to a width of about 0.1 μm. FIB used a Ga ion source at 30 kV.

  FIG. 19A shows an optical microscopic image of a cross-sectional observation location after writing data in the organic memory element, and cross-sectional TEM images of locations corresponding to FIG. 19A are respectively shown in FIGS. 19B and 20A. ) And (B). Further, FIG. 21 shows an optical microscope image of the cross-sectional observation location after data writing, and FIGS. 22A and 22B show cross-sectional TEM images of the location corresponding to FIG. For comparison, FIG. 23 shows a cross-sectional TEM image of the organic memory element before writing. The film thickness of the organic compound layer shown in FIG. 23 was 34 nm. Moreover, the magnification of FIG. 19 (B) is 30000 times, the magnification of FIG. 20 (A) and (B) is 100000 times, and the magnification of FIG. 22 (A), (B), and FIG. 200,000 times.

  As shown in FIG. 23, the film thickness of the organic compound layer before writing is uniform, and is 34 nm here. FIG. 19B is an observation of a TEM transmission image of a cross section at Point (i) in FIG. After the organic memory element is short-circuited as shown in FIG. 19A, many protrusions are observed in a part of the organic memory element. FIG. 19B shows the projection portion observed. The closer to the right side of FIG. 19 (B), the closer to the center of the protrusion in FIG. 19 (A). That is, it can be determined that the protrusion in the organic memory element after the short circuit is caused by a change in the thickness of the organic compound layer of the organic memory element.

  20A and 20B show the organic memory element observed at a higher magnification than that in FIG. In FIGS. 20A and 20B, different portions were observed. The film thickness of the organic compound layer at the left end in FIG. 20A is 90 nm, and the film thickness of the organic compound layer at the left end in FIG. 20B is 15 nm. Thus, it can be seen that the thickness of the organic compound layer of the organic memory element in which data is written is partially different, and the distance between the electrodes changes.

  As shown in FIG. 20A, the protrusion of FIG. 19A in the organic memory element after data writing has a thickness on the organic compound layer of the organic memory element when a voltage is applied to the organic memory element. It can be judged that a change has occurred. Since the film thickness of the organic compound layer is reduced as the distance from the protrusion portion increases as shown in FIG. 20A, the portion corresponding to the protrusions (see Point (ii) in FIG. 21) is observed in FIG. It is.

  As shown in FIGS. 22A and 22B, the organic memory element material is short-circuited after the write voltage is applied because the organic compound layer flows and the first conductive layer and the second conductive layer are in contact with each other. I understand. Strictly speaking, it can be determined from the cross-sectional TEM image of FIG. 22 that the thickness of the organic compound layer is 5 nm or less at the boundary between the first conductive layer and the second conductive layer.

  In this example, in Sample 1 to Sample 6 in which an organic memory element was formed on a substrate as shown in FIG. 27, the measurement result of the current-voltage characteristics when data was electrically written to the organic memory element is shown. Shown in 24-26. Here, writing was performed by applying a voltage to the organic memory element to short-circuit the organic memory element.

  24 to 26, the horizontal axis represents voltage, the vertical axis represents current density value, the circled plots indicate the measurement results of the current-voltage characteristics of the organic memory element before the data was written, and the squared plots represent the data written. The measurement result of the current voltage characteristic of an organic memory element later is shown. Moreover, the magnitude | size in the horizontal surface of the samples 1-6 is 2 mm x 2 mm.

  Sample 1 is an element in which a first conductive layer, a first organic compound layer, and a second conductive layer are stacked in this order. Here, as shown in FIG. 27A, the first conductive layer is formed of ITO containing silicon oxide, the first organic compound layer is formed of TPD, and the second conductive layer is formed of aluminum. . The first organic compound layer was formed with a thickness of 50 nm. The measurement result of the current-voltage characteristic of Sample 1 is shown in FIG.

  Sample 2 is an element in which a first conductive layer, a first organic compound layer, and a second conductive layer are stacked in this order. Here, as shown in FIG. 27B, the first conductive layer is formed of ITO containing silicon oxide, and the first organic compound layer is formed of 2,3,5,6-tetrafluoro-7,7. , 8,8, -tetracyanoquinodimentane (sometimes abbreviated as F4-TCNQ), and the second conductive layer was formed of aluminum. The first organic compound layer was formed to a thickness of 50 nm by adding 0.01 wt% of F4-TCNQ. The measurement result of the current-voltage characteristic of Sample 2 is shown in FIG.

  Sample 3 is an element in which a first conductive layer, a first organic compound layer, a second organic compound layer, and a second conductive layer are stacked in this order. Here, as shown in FIG. 27C, the first conductive layer is formed of ITO containing silicon oxide, the first organic compound layer is formed of TPD, and the second organic compound layer is formed of F4-TCNQ. And the second conductive layer was formed of aluminum. In addition, the first organic compound layer was formed with a thickness of 50 nm, and the second organic compound layer was formed with a thickness of 1 nm. The measurement result of the current-voltage characteristics of Sample 3 is shown in FIG.

  Sample 4 is an element in which a first conductive layer, a first organic compound layer, a second organic compound layer, and a second conductive layer are stacked in this order. Here, as illustrated in FIG. 27D, the first conductive layer is formed using ITO containing silicon oxide, the first organic compound layer is formed using F4-TCNQ, and the second organic compound layer is formed using TPD. And the second conductive layer was formed of aluminum. In addition, the first organic compound layer was formed with a thickness of 1 nm, and the second organic compound layer was formed with a thickness of 50 nm. The measurement result of the current-voltage characteristics of Sample 4 is shown in FIG.

  Sample 5 is an element in which a first conductive layer, a first organic compound layer, a second organic compound layer, and a second conductive layer are stacked in this order. Here, as shown in FIG. 27E, the first conductive layer is formed of ITO containing silicon oxide, the first organic compound layer is formed of TPD to which F4-TCNQ is added, and the second The organic compound layer was formed with TPD, and the second conductive layer was formed with aluminum. In addition, the first organic compound layer was formed to a thickness of 40 nm by adding 0.01 wt% of F4-TCNQ. The second organic compound layer was formed with a thickness of 40 nm. The measurement result of the current-voltage characteristics of Sample 5 is shown in FIG.

  Sample 6 is an element in which a first conductive layer, a first organic compound layer, a second organic compound layer, and a second conductive layer are stacked in this order. Here, as shown in FIG. 27F, the first conductive layer is formed of ITO containing silicon oxide, the first organic compound layer is formed of TPD, and the second organic compound layer is formed of F4-TCNQ. And the second conductive layer was formed of aluminum. The first organic compound layer was formed with a thickness of 40 nm. The second organic compound layer was formed to a thickness of 10 nm and 0.01 wt% of F4-TCNQ was added. The measurement result of the current-voltage characteristics of Sample 6 is shown in FIG.

  Also from the experimental results shown in FIGS. 24 to 26, in Samples 1 to 6, there are significant changes in the current-voltage characteristics of the organic memory element before data writing and before and after the short circuit of the organic memory element. Moreover, in the organic memory elements of these samples, the voltage at which each organic memory element is short-circuited was also reproducible, and the error was within 0.1V.

Next, Table 1 shows the writing voltage of Sample 1 to Sample 6 and the characteristics before and after writing.

  In Table 1, a write voltage (V) indicates an applied voltage when each organic memory element is short-circuited. R (1V) is a value obtained by dividing the current density when 1 V is applied to the organic memory element after writing by the current density when 1 V is applied to the organic memory element before writing. Similarly, R (3 V) is a value obtained by dividing the current density when a voltage of 3 V is applied to the organic memory element after writing by the current density when 3 V is applied to the organic memory element before writing. That is, the current density changes before and after writing in the organic memory element. It can be seen that when 1 V is applied as compared with the case where the applied voltage is 3 V, the change in current density before and after writing of the organic memory element is as large as 10 4 or more.

  In this embodiment, a flexible semiconductor device is described with reference to FIGS.

As shown in FIG. 28A, a 100 nm thick SiON film 6102 was formed on a glass substrate 6101 by plasma CVD. Next, a tungsten film 6103 having a thickness of 30 nm was formed as the separation layer by a sputtering method. Next, a 200 nm-thick SiO ₂ film 6104 was formed in contact with the tungsten film 6103 which is a separation layer by a sputtering method. A 50 nm thick SiNO film 6105, a 100 nm thick SiON film 6106, and a 66 nm thick amorphous silicon film (not shown) were successively formed by plasma CVD.

Next, the glass substrate 6101 was heated at 550 degrees for 4 hours with an electric furnace. By the heating, a tungsten oxide layer (not shown) was formed at the interface between the tungsten film 6103 and the SiO ₂ film 6104 film which are peeling layers. In addition, the amorphous silicon film was crystallized to form a crystalline silicon film.

  Next, after dry etching the crystalline silicon film, a Ti film having a thickness of 60 nm, a TiN film having a thickness of 40 nm, an Al film having a thickness of 40 nm, a Ti film having a thickness of 60 nm, and a TiN film having a thickness of 40 nm are formed by sputtering. A laminated conductive layer was formed. Next, a resist mask was formed by a photolithography process, and the conductive layer was etched using the resist mask as a protective film, whereby a wiring 6107 was formed.

  Next, a Ti film having a thickness of 100 nm was formed on the wiring 6107 and the SiON film 6106 by sputtering. Next, a resist mask was formed by a photolithography process, and the Ti film was etched by a wet etching method using HF using the resist mask as a protective film, whereby a first conductive layer 6108 was formed.

  Next, a photosensitive resin was applied and baked to form a polyimide layer with a thickness of 1.5 μm, and then exposed and developed to form an insulating layer 6109 covering the end portion of the first conductive layer 6108. At this time, part of the first conductive layer 6108 was exposed. Next, an organic compound layer 6110 having a thickness of 30 nm was formed over the insulating layer 6109 and the exposed first conductive layer 6108 by an evaporation method. Here, the organic compound layer was formed using NPB. Next, a second conductive layer 6111 having a thickness of 200 nm was formed by an evaporation method. Here, the second conductive layer 6111 is formed using aluminum.

Next, after applying an epoxy resin, it was baked at 110 ° C. for 30 minutes. Next, a flexible film 6113 was attached to the epoxy resin surface. Next, an adhesive tape was attached to the glass substrate 6101. Next, the flexible film 6113 was bonded to the epoxy resin by heating at 120 to 150 degrees. Next, the glass substrate 6101 is placed on the surface of the flat portion, and an adhesive roller is pressed against the surface of the flexible film 6113, so that the interface between the tungsten film 6103 and the SiO ₂ film 6104 which is a release layer (FIG. 28A The layer having the organic memory element was peeled off by an arrow 6114) (see FIG. 28B).

  FIG. 29 shows a photograph of the organic memory element peeled from the glass substrate 6101 at this time and a schematic diagram thereof.

FIG. 29A is a photograph of the organic memory element formed over the flexible film 6113 taken from the organic memory element side, that is, the SiO ₂ 6104 side. FIG. 29B is a schematic diagram of FIG. A second conductive layer 6111, an insulating layer 6109, and a first conductive layer 6108 are stacked over the flexible film 6113, and a wiring 6107 connected to the first conductive layer 6108 is formed. Note that the organic compound layer 6110 formed on the surfaces of the insulating layer 6109 and the second conductive layer 6111 is indicated by a broken line. Since the organic compound layer 6110 is not colored and has a small thickness, it cannot be visually confirmed in FIGS.

  FIG. 29C is a photograph of the organic memory element shown in FIG. 29A taken from the flexible film 6113 side.

  As described above, a flexible semiconductor device (storage device, memory) in which an organic memory element was provided over a flexible film could be manufactured.

  In the present embodiment, the measurement result of the current-voltage characteristics of the organic memory element when writing is performed by applying a voltage to the first conductive layer and the second conductive layer of the organic memory element and insulating the organic memory element. As shown in FIG.

A first conductive layer is formed on a glass substrate by a sputtering method, and the surface of the first conductive layer is wiped with a polyvinyl alcohol-based porous material to remove dust on the surface. An organic compound layer having a thickness of 20 nm was formed on the organic compound layer, and a second conductive layer having a thickness of 200 nm was formed on the organic compound layer by a vapor deposition method to form an organic memory element. Here, the first conductive layer was formed of titanium, the organic compound layer was formed of Alq ₃ , and the second conductive layer was formed of aluminum. Thereafter, an epoxy resin was applied and heated to seal the organic memory element. At this time, the size of the organic memory element in the horizontal plane was set to 5 μm × 5 μm.

In FIG. 30, the horizontal axis indicates voltage, the vertical axis indicates current value, the plot 6301 indicates the measurement result of the current-voltage characteristics of the organic memory element before writing data, and the plot 6302 indicates the current of the organic memory element immediately after writing. The measurement result of a voltage characteristic is shown. The write voltage at this time was 12V, and the write current value was 5 × 10 ⁻⁴ μA. Further, the current value immediately after writing is 5 × 10 ^{−12 to} 3 × 10 ⁻¹¹ μA, and the current value immediately after writing is decreased. Thus, data can be written by applying a voltage. In addition, data can be read by reading a change in the current value of the organic memory element.

8A and 8B illustrate a semiconductor device and a driving method thereof according to the present invention. 8A and 8B illustrate a semiconductor device and a driving method thereof according to the present invention. 6A and 6B illustrate a semiconductor device of the present invention. 8A and 8B illustrate an example of a manufacturing process of a semiconductor device of the present invention. 6A and 6B illustrate a semiconductor device of the present invention. 6A and 6B illustrate a semiconductor device of the present invention. 8A and 8B illustrate usage patterns of a semiconductor device of the present invention. 8A and 8B illustrate usage patterns of a semiconductor device of the present invention. 8A and 8B illustrate a semiconductor device and a driving method thereof according to the present invention. 8A and 8B illustrate a semiconductor device and a driving method thereof according to the present invention. 8A and 8B illustrate a semiconductor device and a driving method thereof according to the present invention. The figure which shows an example of the laser irradiation apparatus of this invention. FIG. 6 is a measurement diagram of current-voltage characteristics of an organic memory element in a semiconductor device of the present invention. FIG. 6 is a measurement diagram of current-voltage characteristics of an organic memory element in a semiconductor device of the present invention. 6A and 6B illustrate a semiconductor device of the present invention. 3 is an optical microscope image of the semiconductor device of the present invention. FIG. 9 shows writing characteristics of the semiconductor device of the present invention. FIG. 13 shows current-voltage characteristics of a semiconductor device of the present invention. The optical microscope image and cross-sectional TEM image after the data writing of the organic memory element of this invention. The cross-sectional TEM image after the data writing of the organic memory element of this invention. The optical microscope image after the data writing of the organic memory element of this invention. The cross-sectional TEM image after the data writing of the organic memory element of this invention. The cross-sectional TEM image before the data writing of the organic memory element of this invention. The figure which shows the current-voltage characteristic of the organic memory element of this invention. The figure which shows the current-voltage characteristic of the organic memory element of this invention. The figure which shows the current-voltage characteristic of the organic memory element of this invention. The figure which shows an example of the structure of the organic memory element of this invention. 4A and 4B illustrate a semiconductor device of the present invention. 4A and 4B illustrate a semiconductor device of the present invention. The figure which shows the current-voltage characteristic of the organic memory element of this invention.

Explanation of symbols

Reference Signs List 11 power supply circuit 12 clock generation circuit 13 data demodulation / modulation circuit 14 control circuit 15 interface circuit 16 memory 17 data bus 18 antenna 19 reader / writer 20 semiconductor device 21 memory cell 22 memory cell array 23 decoder 24 decoder 25 selector 26 read / write circuit 27 First conductive layer 28 Second conductive layer 29 Organic compound layer 30 Substrate 31 Flexible substrate 32 Laser light irradiation means 33 Insulating layer 34 Insulating layer 35 Element group 36 Substrate 37 Terminal portion 38 Substrate 39 Conductive particle 40 Resin 42 Substrate 43 Flexible substrate 44 Semiconductor layer 45 Semiconductor layer 46 Resistive element 47 Differential amplifier

Claims (4)

Having a memory element having an organic compound layer provided between a pair of conductive layers;
The organic compound layer has a function of irreversibly changing the electrical resistance when irradiated with light ,
The organic compound layer includes a conjugated polymer containing a photoacid generator . A bit line, a word line, and a memory element;
The memory element has a stacked structure of a first conductive layer constituting the bit line, an organic compound layer, and a second conductive layer constituting the word line,
The organic compound layer has a function of irreversibly changing the electrical resistance when irradiated with light ,
The organic compound layer includes a conjugated polymer containing a photoacid generator . A bit line, a word line, a memory element, and a transistor;
The memory element has a stacked structure of a first conductive layer, an organic compound layer, and a second conductive layer,
A gate of the transistor is electrically connected to the word line;
One of the source or drain of the transistor is electrically connected to the bit line,
The other of the source and the drain of the transistor is electrically connected to the first conductive layer,
The organic compound layer has a function of irreversibly changing the electrical resistance when irradiated with light ,
The organic compound layer includes a conjugated polymer containing a photoacid generator . Oite to claim 2 or claim 3,
Having a conductive layer that functions as an antenna;
The conductive device functioning as the antenna is provided in the same layer as the word line or the bit line.